Well, the drawback to the figure 8 (likewise in the equalette) is that if one arm of the equalette cuts, you have the knot loaded across two strands coming out of the same end of the knot.

With the equalette, I've been going with the figure 8 vice overhand for the limiter knots because of the strength difference under usual loading (no failures). Under failures, the kind of loading you mention occurs if a) both strands of one arm are cut or if b) both strands go to one piece of pro and that pro pulls; I have an overhand when and where the whole arm attaches to the pro. The probability of "a" is low enough for me to not be a concern. Regarding "b", I usually pick the most bomber pro I have for this arm; even so, if that pro comes out and the knot rolls it can go ahead and roll until it is stopped by the end of the loop - if it doesn't reset before that.

Majid, you are being a dick.

Edit: The overhand knot I mentioned above when one arm goes to one piece is important (and is shown in the Long/Gaines anchor book). If it is not there then cut the loop of that arm in one place and a rolling knot won't be stopped (unless it resets).